 |
This is the first step in what could be a revolution in wringing freshwater from the sea. When hydrates form, even in the ocean, salt is excluded from the crystalline structure. Melt the hydrate and it separates into distilled water and gas. Build a large enough structure—say, a tube a thousand feet or longer on the shore or in the sea itself—and you could provide freshwater for an increasingly arid planet, which could quite literally change the world. That is exactly the result Marine Desalination Systems founder Michael Max is gunning for.
Max is one of the world’s ranking experts on hydrates, and he isn’t shy about it. Before you can offer a basic greeting, let alone pull out a pen, he is making declarations: “Up to 500 million gallons of freshwater a day, that’s the goal. . . . Ours is the only group making hydrates from seawater. . . . We’re aiming at a new method that will become a primary source of freshwater on the planet.” At 5 feet 8 inches, Max, 62, is rugby-player stocky with bushy eyebrows, a thick mustache, and all the subtlety of a bulldozer. Arms crossed, he spews out mile-a-minute descriptions of thousand-foot shafts in the sea, where the familiar physics of crystallization, gravity, and pressure gradients will separate salt and produce distilled water.
The key ingredient is gas hydrate, a substance that forms when hydrocarbon gases like methane and ethane come into contact with water at the right temperature and pressure. Gas molecules become trapped inside a lattice structure of water, creating a crystal substance known as clathrate that is superficially similar to ice—except this stuff is flammable. (For more on naturally occurring hydrates, see “Will the Methane Bubble Burst?” in the March 2004 issue of Discover.)
Prior to the 1970s, hydrates were thought of only as nuisances, because they can plug oil and gas pipelines in the field. In the past few decades, however, interest in hydrates has soared, especially in petroleum-poor countries like Japan. Gargantuan stores of gas hydrates under the oceans and permafrost regions of the globe have many scientists wondering whether they can find an economically feasible way to unlock the methane, creating a natural gas supply that could last for centuries. For Max, though, it’s not the gas component of hydrates that has him transfixed; it’s the surrounding molecules of H20.
Max’s curiosity about hydrates began during the 1980s, when he worked as a marine geophysicist for the Naval Research Laboratory. The Navy wanted to know if hydrates under the seafloor were interfering with acoustic signals picked up by an underwater hydrophone array used by the military to track Soviet subs. As the properties, quantities, and potential impact of this mysterious substance began to add up, Max became hooked.
In the mid-1990s, Peter Brewer, a high priest of hydrate research, assisted by Keith Kvenvolden of the U.S. Geological Survey, used a remotely operated vehicle off the California coast to see if releasing compressed gas into small tubes of seawater at depth would result in the spontaneous formation of hydrate. It did, almost instantly. Brewer, who works at the Monterey Bay Aquarium Research Institute, took a video from the experiments to the Naval Research Laboratory in Washington, D.C. “When we showed the video, the response was: ‘Wow. We never knew you could do that,’” recalls Brewer.
“That was truly a seminal moment in hydrate research,” Max says. “When I looked at that video and saw the hydrate floating to the top of those tubes underwater, I thought, ‘What if we had a tube going all the way from where hydrates form at depth to the [ocean] surface?” Max knew what would happen—or should happen—and his desalination idea was born.
